Process for obtaining transparent effects on regenerated cellulose fibers



Patented May 2, 195% PROCESS FOR. OBTAINING TRANSPARENT EFFECTS ON REGENERATED CELLULOSE FIBERS Paullwalter. Steinlin, Basel, Switzerland, assignor' to Aktiengesellschaft Cilander, Herisau, Switzerl'and NoDrawing. Application July 31, 1946, Serial No.

687,512; InSwitzerland April 22, 1943 6. Claims.

The present application is in the nature of a continuation in part of my earlier copending application Serial No; 533,788, filed May 2, 19%, now abandoned.

Transparent fabrics, also known as organdies, have as a rule been made from pure cotton materials, in particular muslin, or, more rarely, voile or other fine fabrics, such as cambric, etc. Organdies of especially fine quality were made of natural silk.

The process hereafter described relates to the production of plain or patterned, smooth or crepe transparent fabricsfrom materials consisting of staple fibre made from regenerated cellulose alone or of staple fibre made from regenerated cellulose and cotton, or of mixed" cotton and staple fibre made from regenerated cellulose.

Various experiments were made in the past to transform textiles of this kind by the ordinary methods used for cotton fabrics. However, even by varyin and adapting working conditions, such as. concentration of. acids and alkaline swelling agents, and the duration of the procedure, it proved impossible to turn out marketable goods. Indeed the materials. hitherto produced were horny, brittle, and stiffened, and in no way suited for practical use. The present process, on the contrary, producesmtransparent fabrics which perfectly satisfy all. requirements as to appearance, lustre, softness and durability, and show a high degree of transparency combined with a remarkable clearness of weave.

These effects are obtained by subjecting the fabric, eventually after preparatory or supplementary treatment with alkaline or acid swelling agents, to a first treatment with hot alkali, neutralizing and rinsing, and then treating it with strong, cold alkali.

By alkali treatment an ordinary mercerizing treatment is understood, with alkali of at least 15 Baum, at temperatures of between -5 and +25 C. and lasting at least 5 seconds.

By hot alkali is understood a treatment according to the present process with hot alkali solution of mercerizing strength, at a temperature of 25 C. or over, having a duration of 5 seconds or more.

A special embodiment of the process consists in drying the fabric between the treatment with 1 hot alkali and that with cold alkali.

The process is suited for fabrics made of pure staple fibre, or woven with cotton and staple fibre, and also for those woven with mixed yarn made from cotton and staple fiber made from til regenerated cellulose. Naturally materials in Which any or all of the above combinations are present, either in. plain or pattern weave, includmg of course applications with embroidery or Swissdotted weave, can also be treated by my process.

It is advantageous to delubricate and bleach the fabric to be processed. Crude fabrics can, however, be treated in the same way. In this connection it should be; borne inmind that, according to the invention, this processing is suitable for usein any phase of pres-treatment.

My process can; be used to advantage-in com-- bination with treatment by swellingagents. The manner and order in which these treatments are applied depend onthe; result desired.

It is not necessary to neutralize or dry the fabric between two consecutive alkaline treatments. -Nevertheless the efiect is heightened byso doing.

Repeating the: process several times also tends in the same direction. Such repetition canapply to the whole process or to a part of. same.

Patterned. as well asplain transparent fabrics can be obtained with the. present. process. by applying. suitable reserves before the swelling. treatment. For example imago effects can be achieved by printing with pigments, resulting in opaque non-transparent. patterns. By this method it is possible, according to. the type of process. chosen, to use pigment. carriers proof against. acid andtalkaline swelling agents, such as gums or artificial resins, which result in local opaque effects, or non-acidproof thickening agents which produce stiifened transparent designs in which the effect of contrast is due to the pigmentation alone. It is moreover possible to introduce reserves during any phase of the transforming process so as to achieve, for example, a transparent efiect and then, by rinsing and subsequent swelling and shrinking, obtain the appearance of crepe. It is also possible to get intermediary effects by the imprint of swelling agents and subsequent treatment with hot alkali. The reserves can even be applied during various phases of the process in such a way that the transformed. material shows untreated and swollen, that is shrunken and transparent areas one next to the other.

It is evident by printing in colours or by the use of coloured reserves such effects can be obtained in various tints.

Fabrics submitted to the present process can be dyed either before or after treatment. In this way, according to the method of procedure,

the most varied results can be obtained, such as plain transparent, or, according to the different afiinity for the dye caused by different local treatment, shaded effects.

My process may be illustrated by means of a single example:

A fabric made from staple fibre made from regenerated cellulose, after being singed, bleached and tentered, is treated with NaOH of 30 B. at 50 C. for 10 seconds. It is then neutralized and rinsed and subjected to the action of NaOH of 30 B. at 10 C. for 5 seconds.

In another embodiment of the process, after neutralization and rinsing, the fabric is dried and then subjected to the finishing treatment with cold alkali.

In both cases the result is a brilliant, transparent weave with pleasant soft feel.

I claim:

1. A multiple step process for obtaining transparent effects on a fabric consist ng predominantly of regenerated cellulose staple fibers com prising treating said fabric with a hot caustic soda of mercerizing strength at temperatures of the order of 50 C. for a period of time of the order of 5 to seconds, removing free caustic soda from the fabric, and then treating said fabric with caustic soda of mercerizing strength at a temperature of 5 to 25 C. for at least 5 seconds but not substantially more than 5 seconds.

2. A multiple step process for obtaining transparent effects on a fabric consisting predominantly of regenerated cellulose staple fibers comprising treating said fabric with caustic soda of the order of 30 Baum at a temperature of the order of 50 C. for a period of time of the order of 5 to 10 seconds, and then treating said fabric with caustic soda of the order of 30 Baum at a temperature of -5 to 25 C. for a period of time of the order of at least 5 seconds but not substantially more than 5 seconds.

3. A multiple step process for obtaining transparent effects on a fabric consisting predominantly of regenerated cellulose staplefibers comprising treating said fabric with caustic soda of the order of 30 Baum at a temperature of the order of 50 C. for a period of time of the order of 5 to 10 seconds, removing free caustic soda from the fabric, and then treating said fabric with caustic soda of the order of 30 Baum at a temperature of 5 to 25 C. for a period of time of the order of at least 5 seconds but not substantially more than 5 seconds.

4. A multiple step process for obtaining transparent effects on a fabric consisting predominantly of regenerated cellulose staple fibers comprising treating said fabric with caustic soda of the order of 30 Baum at a temperature of the order of C. for a period of time of the order of 5 to 10 seconds, rinsing and drying said fabric, and then treating said fabric with caustic soda of the order of 30 Baum at a temperature of -5 to 25 C. for a period of time of the order of at least 5 seconds but not substantially more than 5 seconds.

5. A multiple step process for obtaining transparent effects on a fabric consisting predominantly of regenerated cellulose staple fibers comprising treating said fabric with caustic soda of the order of 30 Baum at a temperature of the order of 50 C. for a period of time of the order of 5 to 10 seconds, neutralizing, rinsing and drying said fabric, and then treating said fabric with caustic soda of the order of 30 Baum at a temperature of --5 to 25 C. for a period of time of the order of at least 5 seconds but not substantially more than 5 seconds.

6. A multiple step process for obtaining trans parent effects on a fabric consisting predominantly of regenerated cellulose staple fibers comprising treating said fabric with caustic soda of the order of 30 Baum at a temperature of the order of 50 C. for a period of time of the order of 5 to 10 seconds, neutralizing and rinsing said fabric, and then treating said fabric with caustic soda of the order of 30 Baum at a temperature of -5 to 25 C. for a period of time of the order of at least 5 seconds but not substantially more than 5 seconds.

PAUL WALTER STEINLIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,439,517 Heberlein Dec. 19, 1922 1,625,438 Voegeli Apr. 26, 1927 1,717,870 Bosshard June 18, 1929 1,989,100 Lilienfeld Jan. 29', 1935 1,998,576 Heberlein Apr. 23, 1935 2,202,200 Haller et a1 May 28, 1940 FOREIGN PATENTS Number Country Date 273,327 Great Britain Aug. 9, 1928 337,713 Italy Mar. 11, 1936 

1. A MULTIPLE STEP PROCESS FOR OBTAINING TRANSPARENT EFFECTS ON A FABRIC CONSISTING PREDOMINANTLY OF REGENERATED CELLULOSE STAPLE FIBERS COMPRISING TREATING SAID FABRIC WITH A HOT CAUSTIC SODA OF MERCERIZING STRENGTH AT TEMPERATURES OF THE ORDER OF 50*C. FOR A PERIOD OF TIME OF THE ORDER OF 5 TO 10 SECONDS, REMOVING FREE CAUSTIC SODA FROM THE FIBER, AND THEN TREATING SAID FABRIC WITH CAUSTIC SODA OF MERCERIZING STRENGTH AT A TEMPERATURE OF -5* TO 25*C. FOR AT LEAST 5 SECONDS BUT NOT SUBSTANTIALLY MORE THAN 5 SECONDS. 